284th ENMC International Workshop: Cognitive and behavioral abnormalities in pediatric DM1; what should we measure in preparation for clinical trials? Hoofddorp, The Netherlands, January 24-26 2025.

In anticipation to clinical trials in pediatric DM1, the 284th ENMC workshop aimed to establish diagnostic and management protocols for CNS involvement based on international expert-consensus by 1) reviewing existing translational research findings on CNS involvement in pediatric DM1, 2) sharing current clinical and diagnostic approaches to CNS involvement in the international pediatric DM1 population and 3) discuss protentional CNS biomarkers relevant to future clinical and research applications in pediatric DM1. Patient and family perspectives on the impact on quality of life were considered. The workshop highlighted the complexity of the spectrum of CNS involvement from a research and clinical care perspective and confirmed the need for international harmonization of clinical assessment of cognitive-behavioral abnormalities. Consensus was reached on 1) disease classification based on age of symptom-onset and 2) a core neuropsychological assessment protocol to be used in clinical practice. Implications for trial design and further research are discussed.